 public class Example4_20 { 

   public static void main(String args[ ]) { 

      char a[]={'a','b','c','D','E','F'};

      for(int i=0;i<a.length;i++) { 

         if(Character.isLowerCase(a[i]))    

             a[i]=Character.toUpperCase(a[i]);

         else if(Character.isUpperCase(a[i]))

             a[i]=Character.toLowerCase(a[i]);

       }

      for(int i=0;i<a.length;i++)   

         System.out.print(" "+a[i]);

 

   } 

}
